ORA_CMR_IGNORE_AP_ERV_TERV profile value unclear

We need to ignore Invoice Exchange Rate Variances for Inventory and Expense.
That's why we want to use the ORA_CMR_IGNORE_AP_ERV_TERV profile.
But we didn't find in any documentation what each option does:
Match to order
Match to receipt
Match to order and match to receipt.

What is the difference between each option?
What does each one do?